Alarm switch and door lock



June 19, 1928. 1,674,570

" A. RE V ALARM SWITCH AND DOOR LOCK Filed March 7, 1927 Patented June 19, 192%.

UNITED STATES ALFRED RE, OF NEW YORK, N. Y.

ALARM SWITCH AND DOOR LOCK.

Application filed March 7, 1927.

The present invention relates to alarm switches for door locks, and aims to provide in combination with a switch or circuit controller operated by the opening of a door, a second switch controlling the circuit and arranged to be operated by the lock of the door, in order that when the lock bolt is retracted by the use of a proper key, the alarm will not be given, whereas if the door is forced open without using the key, the alarm is given.

Another object is to provide a switch de vice adapted to be secured to a door adjacent to the door lock, with novel means for controlling the switch device from the belt of the lock.

With the foregoing and other objects in view. which will be apparent as the description proceeds. the invention resides in the construction and arrangement of parts, as hereinafter described and claimed, it being understood that changes can be made with-,

in the scope of what is claimed, without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawing, wherein Figure 1 is an inside elevation of a door illustrating the improved switch device thereon.

Fig. 2 is an enlarged elevation of the door lock and switch device, a portion of the door lock case being broken away and shown in section and the face plate of the switch Case being removed.

Fig. 3 is a diagrammatical view illustrating the electrical circuit.

Fig. 4. is a diagrammatical view illustrating a modification.

The numeral 7 indicates any suitable door lock having the case 8 in which the lock bolt 9 is slidable to be projected into the usual keeper for locking the door closed, said boltbeing retracted in the usual manner by the use of a proper key.

In carrying out the invention there is provided a switch device 10 secured to the door adjacent to the lock 7. As shown, the switch device 10 is located above the lock. The switch device comprises a case 11 having a block 12 of insulating material therein to which are secured the leaf springs 13 and 14, and wires 15 of an electrical circuit are connected with said leaf springs. The leaf spring 14 has its terminal portion bent toward the leaf spring 13 and bent reversely Serial No. 173,448.

to form a contact 16 to engage a portion 17 of the leaf spring 13 which is bent toward the spring 14, and the portion 17 has an outturncd portion 18. The contact 17 of the spring 13 normally bears against the contact 16 of the spring 14, to close the circuit at this point.

In order to control the circuit by the movement of the lock bolt 9, a plunger 19 is slidable through the wall of the case 11 with its inner end adapted to abut the abutment 18 of the sprEng 13, and the case S of the lock is provided with a slot 20 to receive said plunger and to also accommodate a cam piece 21 which is secured in any suitable manner to the bolt 9. The piece 21 has a cam 22 arranged to engage the corresponding end of the plunger 19 and slide said plunger. when the bolt 9 is retracted by the use of the appropriate key, in order that the plunger 19 bearing against the abutment- 18 will flex the spring 13 away from the spring let so as to separate the contacts 16 and 17. Thus, when the lock bolt 9 is retracted by the operation of the lock, when using the appropriate key, the circuit is opened between the contacts 16 and 17.

As seen in Fig, 3, the circuit of the cont-acts 16 and 17 includes a suitable electric bell or other audible or visual signal device 28 and battery 2st or other source of electrical energy, and the circuit also includes a switch device or contacts between the door and door frame, and any suitable switch device or circuit controller may be used for this purpose so that when the door is opened the circuit is closed at this point. Therefore, if the door is forced open with out retracting the lock bolt 9. the circuit is completed at the switch device 25 and the contacts 16 and 17 being in engagement, will result in the circuit being completed so that the alarm is given. However, when the key is inserted in the lock and the lock bolt retracted, the cam 22 sliding the plunger 19 will open the circuit between the contact", 16 and 17 so that even though the switch device 25 is ClOfGCl, the circuit remains broken, and the alarm will not be given.

In order to prevent the alarm being given when not desired. such as during the daytime or when the key is withdrawn from the lock after the door has been opened and before the door is again closed. a lever 25 is pivoted, as at 26, in the case 11 and has a llll 2 r 7 emma that the contact 17 returns into engagement with the contact 16, following the opening of the switch device 25 when the door has been closed. The lever may also be used,

for opening the circuit during the daytime. Fig. at lllustrates modification; for use in a normally closed circuit, which when broken will give the alarm. lhus, the

switch'device 25 and contacts 16 and17 are connected in parallel with one another 3 for a normally open circuit. The contacts 16 and11 7' of the springs 14 and 13, respectively, are normally separated, and when the plunger 19 is moved by thecam piece 21, the plunger bearing againit the abutment 18, of the leaf spring 1% will flex said spring 14 toward the spring 13 to move the contact 16 against the contact 17.

I Thus, the circuit is closed between the contact-s 16' and 17 by the operation of the lock in retracting the lock bolt 9, so that the circuit will not be interrupted when'the doorv is opened and theswitch device 25 opened. It will thus be obvious that the improve ments may be used for either normally open or normally closed circuits, and the switch device 10enables the circuit to be controlled from the ordinary or anysuitable lock, withoutthe necessity for combining the device i with the lock for enclosing same in the-lock caseis claimed as new is contacts, means for flexing one of Having thus described the invention, what 7 1. The combination with a door lock having a slidable bolt, of a switch device comprising two leaf springs having cooperable said springs when "said bolt is moved, and means for flexing one of said springs independently of the movement'o'f said bolt.

2.'The combination with a door lock including a slidable bolt, of aswitch' device comprising two leaf sorings having cooperable contacts, a plunger to abut one spring and flex it relatively to the other spring, a cam carried by said bolt 1 to move said plunger, and other means for flexing one of said springs independently ofthe movement of the plunger by said cam,

3. The combination with a door locl; in-' case and having 'cooperable contacts, a.

plunger slidablt in the second named case and arranged to abut one spring to flex t relatively to the other spring, and a cam piece carried by said bolt to engagesaid plunger.

4. The combination with a door lock mcluding a case and a bolt slidable therein, of

a switchdevice comprising a case, two leaf springs mounted in therecond named case and having cooperable contacts, a plunger slidable in the second named case and an ranged to abut one spring to flex it rela-V tively to the other spring, a cam piece carried by said bolt to engage said plunger, and a lever pivoted in the second named case and having a carnto, contact with one spring for flexing it away from the other spring.

7 In testimony whereof I hereunto aflix my signature. 1

ALFRED an. 

